DESCRIPTION: (provided by the applicant): Anopheles darlingi remains the major Neotropical malaria vector in Brazil, but its importance may be diminishing in some ecologically altered environments, while increasing in others. Anopheles marajoara has been newly incriminated as the primary vector around the city of Macapa in Amapa state, Amazonian Brazil. Anopheles marajoara's importance in transmission appears to be increasing in disturbed habitats in this region. Changes in vector species may alter the epidemiology of malaria transmission in the Amazon. The overall goal of this project is to characterize and explain aspects of ecology, genetics and epidemiology of each of An. Marajoara and An. Darlingi in northeastern Amazonian Brazil. Among outcomes, this research may explain changing patterns of distribution of An. Darlingi and An. Marajoara in disturbed environments, along with providing insights to predict such changes in other vector species. The first specific aim of the proposal is to account for current patterns of distribution, abundance and infectivity of An. Marajoara and An. Darlingi by testing hypotheses in two ecoregions, savanna and lowland rainforest, and in agricultural settlements and gold mines. This will be investigated using field collections and ELISA. The second specific aim tests hypotheses of population structure, genetic diversity, differentiation and effective population size from representative population samples in the presence of ecological disturbance. Markers used are microsatellites and mitochondrial DNA Col gene sequences. Specific aim three examines potential changes in epidemiological patterns that might be expected to accompany ecological disturbance and will use data collected by the Brazilian government agency Fundacao Nacional da Saude to compare several locations in Amazonian Brazil. The fourth specific aim uses microsatellite markers to examine An. Darlingi in each of Manaus and Belem to determine the source of the documented reestablished populations, whether nearby or distant, and the extent of gene flow among all populations in and around each city.